Molded proximity sensor

ABSTRACT

A proximity sensor includes a printed circuit board substrate, a semiconductor die, electrical connectors, a lens, a light emitting assembly, and an encapsulating layer. The semiconductor die is positioned over the printed circuit board substrate with its upper surface facing away from the printed circuit board substrate. Each of the electrical connectors is in electrical communication with a contact pad of the semiconductor die and a respective contact pad of the printed circuit board substrate. The lens is positioned over a sensor area of the semiconductor die. The light emitting assembly includes a light emitting device having a light emitting area, a lens positioned over the light emitting area, and contact pads facing the printed circuit board substrate. The encapsulating layer is positioned on the printed circuit board substrate, at least one of the electrical connectors, the semiconductor die, the lens, and the light emitting assembly.

BACKGROUND

Technical Field

The present application generally relates to semiconductor devices, andmore particularly to semiconductor proximity sensor devices.

Description of the Related Art

FIG. 1A is a top plan view of a conventional proximity sensor 100. Theproximity sensor 100 includes a cap 102 having a first aperture 104 anda second aperture 106 formed therein. FIG. 1B is a cross-sectional viewof the proximity sensor 100 along the line IB-IB shown in FIG. 1A. Theproximity sensor 100 includes a light emitting device 108 and asemiconductor die 110 disposed on a printed circuit board substrate 112.A sensor area 114 is disposed on an upper surface of the semiconductordie 110. A lens 116 is secured to the semiconductor die 110 above thesensor area 114 using a transparent adhesive material 118.Alternatively, a pair of the lenses 116 may be secured to the cap 102using an adhesive such that light passing through the first aperture 104and the second aperture 106 also passes through the lenses 116. Thelight emitting device 108 emits light through the first aperture 104.The light emitted by the light emitting device 108 that is reflected byan object in the vicinity of the proximity sensor 100 may enter thesecond aperture 106, travel through the lens 116, and impact the sensorarea 114. The proximity sensor 100 outputs a signal indicative of theintensity of light that is incident on the sensor area 114.

As shown in FIG. 1B, the cap 102 includes a first cap piece 102 a, asecond cap piece 102 b, and a third cap piece 102 c. The cap pieces 102a-102 c are extremely small, generally having dimensions between 15micrometers and 150 micrometers. The first cap piece 102 a is secured tothe printed circuit board substrate 112 using an adhesive material 120a. The second cap piece 102 b is secured to the semiconductor die 110using an adhesive material 120 b. The third cap piece 102 c is securedto the printed circuit board substrate 112 using an adhesive material120 c.

During fabrication of the proximity sensor 100, the adhesive material120 a and the adhesive material 120 c are deposited on an upper surfaceof the printed circuit board substrate 112, and the adhesive material120 b is deposited on an upper surface of the semiconductor die 110. Thetiny cap pieces 102 a-102 c are carefully positioned on the adhesivematerials 120 a-120 c, respectively. If the cap pieces 102 a-102 cand/or the adhesive materials 120 a-120 c are not precisely placed intheir intended locations, the cap pieces 102 a-102 c may not adhereproperly and/or may not form the apertures 104 and 106 over the lightemitting device 108 and the sensor area 114, respectively. Thus,fabrication of the proximity sensor 100 may result in a high defectrate, which can increase manufacturing costs.

Accordingly, proximity sensor devices that can be fabricated with lowerdefect rates are needed.

BRIEF SUMMARY

According to an embodiment, a proximity sensor device is provided. Thedevice includes a first printed circuit board substrate, a semiconductordie, a plurality of electrical connectors, a first lens, a lightemitting assembly, and an encapsulating layer. The first printed circuitboard substrate includes a first plurality of contact pads on a firstside of the first printed circuit board substrate. The semiconductor dieincludes a sensor area on an upper surface and a second plurality ofcontact pads. The semiconductor die is positioned over the first printedcircuit board substrate with its upper surface facing away from thefirst printed circuit board substrate. Each of the electrical connectorsis in electrical communication with one of the second plurality ofcontact pads and a respective one of the first plurality of contactpads. The first lens is positioned over the sensor area of thesemiconductor die. The light emitting assembly includes a light emittingdevice having a light emitting area, a second lens positioned over thelight emitting area, and a third plurality of contact pads facing thefirst printed circuit board substrate. The encapsulating layer ispositioned on the first printed circuit board substrate, at least one ofthe plurality of electrical connectors, the semiconductor die, the firstlens, and the light emitting assembly.

According to another embodiment, a proximity sensor is provided. Theproximity sensor includes an encapsulating layer, a plurality of capfeet, a plurality of lenses, a light emitting device, and asemiconductor die. The encapsulating layer has a first side and a secondside. The cap feet are in contact with and extend from the first side ofthe encapsulating layer. Each of the lenses has a first side and asecond side. The encapsulating layer is in contact with the first sideand the second side of each of the lenses. The light emitting device isdisposed below a first one of the lenses. The semiconductor die includesa sensor area that disposed below a second one of the lenses.

According to yet another embodiment, a method for manufacturing aproximity sensor device is provided. According to the method, asemiconductor die is positioned on a first side of a first printedcircuit board substrate. A first plurality of electrical connections isformed between the semiconductor die and the first printed circuit boardsubstrate. A first lens is positioned over a sensor area of thesemiconductor die. The first lens is attached to the semiconductor die.A light emitting assembly is positioned on the first side of the firstprinted circuit board substrate. The light emitting assembly includes alight emitting device and a second lens positioned over a light emittingarea of the light emitting device. A second plurality of electricalconnections is formed between the light emitting assembly and the firstprinted circuit board substrate. An encapsulating layer is formed on thefirst printed circuit board substrate, at least one of the secondplurality of electrical connections, the semiconductor die, the firstlens, and the light emitting assembly.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1A is a top plan view of a conventional proximity sensor.

FIG. 1B is a cross-sectional view of the proximity sensor shown in FIG.1A.

FIGS. 2A-2D show a semiconductor assembly at various stages offabrication, according to one embodiment.

FIG. 3 is a cross-sectional view of a light emitting assembly, accordingto one embodiment.

FIG. 4 is a block diagram of a communication device, according to oneembodiment.

FIGS. 5A-5E show a semiconductor assembly at various stages offabrication, according to one embodiment.

FIG. 6A is a top view of a proximity sensor, according to oneembodiment.

FIG. 6B is a cross-sectional view of the proximity sensor shown in FIG.6A.

FIG. 7A is a top plan view of a proximity sensor, according to oneembodiment.

FIG. 7B is a cross-sectional view of the proximity sensor shown in FIG.7A.

FIG. 8A is a top plan view of a proximity sensor, according to oneembodiment.

FIG. 8B is a cross-sectional view of the proximity sensor shown in FIG.8A.

FIG. 9A is a top plan view of a proximity sensor, according to oneembodiment.

FIG. 9B is a cross-sectional view of the proximity sensor shown in FIG.9A.

FIG. 10A is a top plan view of a proximity sensor, according to oneembodiment.

FIG. 10B is a cross-sectional view of the proximity sensor shown in FIG.10A.

FIG. 11A is a top plan view of a proximity sensor, according to oneembodiment.

FIG. 11B is a cross-sectional view of the proximity sensor shown in FIG.11A.

FIGS. 12A-12H show a proximity cap assembly at various stages offabrication, according to one embodiment.

FIG. 13A is a top view of a proximity sensor cap, according to oneembodiment.

FIG. 13B is a cross-sectional view of the proximity sensor cap shown inFIG. 13A.

FIG. 14 is a cross-sectional view of a proximity sensor, according toone embodiment.

DETAILED DESCRIPTION

FIGS. 2A-2D show a semiconductor assembly 200 at various stages offabrication, according to one embodiment. As shown in FIG. 2A, thesemiconductor assembly 200 includes a printed circuit board substrate202. An upper surface of the printed circuit board substrate 202includes a plurality of contact pads 204. A lower surface of the printedcircuit board substrate 202 includes a plurality of contact pads 206. Aplurality conductive traces 208 form electrical connections between oneor more of the contact pads 204 on the upper surface of the printedcircuit board substrate 202 and one or more of the contact pads 206 onthe lower surface of the printed circuit board substrate 202.

As shown in FIG. 2B, a plurality of light emitting devices 210 is placedover the upper surface of the printed circuit board substrate 202. Inone embodiment, each of the light emitting devices 210 is a conventionallight emitting diode (LED). In one embodiment, each of the lightemitting devices 210 is a conventional vertical-cavity surface-emittinglaser (VCSEL).

An upper surface of each light emitting device 210 includes a lightemitting area 212 and a contact pad 214. A conventional conductiveadhesive material 216 forms an electrical connection between a lowersurface of each light emitting device 210 and one of the contact pads204 on the upper surface of the printed circuit board substrate 202. Theconductive adhesive material 216 secures each light emitting device 210to the upper surface of the printed circuit board substrate 202.

In one embodiment, the conductive adhesive material 216 is formed onpredetermined ones of the contact pads 204 on the upper surface of theprinted circuit board substrate 202 and then the lower surfaces of thelight emitting devices 210 are placed in contact with the conductiveadhesive material 216. In one embodiment, at least part of the lowersurface of each of the light emitting devices 210 is coated with theconductive adhesive material 216, which is then placed in contact with apredetermined one of the contact pads 204 on the upper surface of theprinted circuit board substrate 202. For example, pick-and-placemachinery employing conventional surface mount technology may be used toplace the light emitting devices 210 on the upper surface of the printedcircuit board substrate 202.

As shown in FIG. 2C, electrical connections are then formed between thecontact pads 214 on the upper surfaces of the light emitting devices 210and corresponding contact pads 204 on the upper surface of the printedcircuit board substrate 202. In one embodiment, conventional wirebonding machinery connects one end of each of a plurality of wires 218to one of the contact pads 204 on the upper surface of the printedcircuit board substrate 202 and then connects the other end of the wire218 to one of the contact pads 214 on the upper surface of a respectiveone of the light emitting devices 210.

As shown in FIG. 2D, a layer of a conventional transparent material 220is then formed on the upper surface of the printed circuit boardsubstrate 202 and upper and side surfaces of each of the light emittingdevices 210 and the wires 218. Initially, the transparent material 220may be in a liquid or gel form and may be poured or injected over theprinted circuit board substrate 202, the light emitting devices 210, andthe wires 218. The transparent material 220 may then be cured with UVlight, heat, and/or moisture to cause the transparent material 220 totake a solid form more quickly.

The transparent material 220 may enable most, if not all, of the lightincident on the transparent material 220 to pass therethrough. Forexample, the transparent material 220 may enable at least 85% of thelight in the visible spectrum (e.g., wavelengths of light fromapproximately 400 nanometers to 700 nanometers) or light in the infraredspectrum (e.g., wavelengths of light from approximately 700 nanometersto 1250 nanometers) that is incident on the transparent material 220 topass therethrough. Additionally or alternatively, the transparentmaterial 220 may act as a filter that prevents predetermined wavelengthsof light from passing therethrough. For example, the transparentmaterial 220 may prevent light in the visible spectrum or light in theinfrared spectrum that is incident on the transparent material 220 frompassing therethrough.

With reference to FIGS. 2D and 3, the semiconductor assembly 200 is thensawed or otherwise separated to form a plurality of light emittingassemblies 300. For example, the blade of a saw is placed on the uppersurface of the semiconductor assembly 200 at the location 222 and thenmoved downwardly until the blade passes through the layer of thetransparent material 220 and the printed circuit board substrate 202.

FIG. 3 is a cross-sectional view of the light emitting assembly 300. Thelight emitting assembly 300 includes the printed circuit board substrate202. An upper surface of the printed circuit board substrate 202includes the contact pads 204. A lower surface of the printed circuitboard substrate 202 includes the contact pads 206. The conductive traces208 form electrical connections between one or more of the contact pads204 on the upper surface of the printed circuit board substrate 202 andone or more of the contact pads 206 on the lower surface of the printedcircuit board substrate 202.

The light emitting device 210 is disposed on the upper surface of theprinted circuit board substrate 202. An upper surface of the lightemitting device 210 includes the light emitting area 212 and the contactpad 214. The conductive adhesive material 216 forms an electricalconnection between a lower surface of the light emitting device 210 andone of the contact pads 204 on the upper surface of the printed circuitboard substrate 202. The wire 218 forms an electrical connection betweenthe contact pad 214 on the upper surface of the light emitting device210 and one of the contact pads 204 on the upper surface of the printedcircuit board substrate 202. A lens 302 is formed by the transparentmaterial 220.

FIG. 4 is a block diagram of a communication device 400, according toone embodiment. The communication device 400 includes a proximity sensor402, a controller 404, and a display device 406. In one embodiment, thecommunication device 400 is a cellular telephone, the proximity sensor402 is the proximity sensor 600 shown in FIGS. 6A and 6B, and thedisplay device 406 is a touchscreen device. If the proximity sensor 402is not near the body of a user, for example, the proximity sensor 402outputs to the controller 404 a first signal indicating that little, ifany, light output from the proximity sensor 402 has been reflected fromthe user's body and returned to the proximity sensor 402. When thecontroller 404 receives the first signal from the proximity sensor 402,the controller 404 provides to the display device 406 a first controlsignal that enables the display device 406 and/or causes a back light ofthe display device 406 to output a predetermined maximum amount oflight.

The proximity sensor 402 may be located near a speaker (not shown) ofthe communication device 400. If the proximity sensor 402 is positionednear the user's body (e.g., the user's ear) the proximity sensor 402outputs to the controller 404 a second signal indicating that at least apredetermined amount of light output from the proximity sensor 402 hasbeen reflected from the user's body and returned to the proximity sensor402. When the controller 404 receives the second signal from theproximity sensor 402, the controller 404 provides to the display device406 a second control signal that disables the display device 406 and/orcauses the back light of the display device 406 to output apredetermined minimum amount of light. Accordingly, the proximity sensor402 may be used to reduce power consumption of the communications device400.

FIGS. 5A-5E show a semiconductor assembly 500 at various stages offabrication, according to one embodiment.

As shown in FIG. 5A, the semiconductor assembly 500 includes a printedcircuit board substrate 502. An upper surface of the printed circuitboard substrate 502 includes a plurality of contact pads 504. A lowersurface of the printed circuit board substrate 502 includes a pluralityof contact pads 506. A plurality conductive traces 508 form electricalconnections between one or more of the contact pads 504 on the uppersurface of the printed circuit board substrate 502 and one or more ofthe contact pads 506 on the lower surface of the printed circuit boardsubstrate 502.

A plurality of conventional semiconductor dice 510 is placed over theupper surface of the printed circuit board substrate 502. For example,pick-and-place machinery employing conventional surface mount technologymay be used to place the semiconductor dice 510 on the upper surface ofthe printed circuit board substrate 502. An upper surface of eachsemiconductor die 510 includes a sensor area 512 and contact pads 514.In one embodiment, the sensor area 512 is part of a photodiode thatconverts light into current, wherein the magnitude of the current isproportional to the magnitude of the intensity of the light.

As shown in FIG. 5B, a plurality of the light emitting assemblies 300 isplaced over the upper surface of the printed circuit board substrate502. For example, pick-and-place machinery employing conventionalsurface mount technology may be used to place the light emittingassemblies 300 over the upper surface of the printed circuit boardsubstrate 502.

A conductive adhesive material 516 secures the semiconductor dice 510and the light emitting assemblies 300 to the upper surface of theprinted circuit board substrate 502. Additionally, the conductiveadhesive material 516 forms an electrical connection between the lowersurface of each semiconductor die 510 and one of the contact pads 504 onthe upper surface of the printed circuit board substrate 502. Theconductive adhesive material 516 also forms an electrical connectionbetween each of the contact pads 206 on the lower surface of each lightemitting assembly 300 and a respective one of the contact pads 504 onthe upper surface of the printed circuit board substrate 502.

As shown in FIG. 5C, electrical connections are formed between the atleast one contact pad 514 on the upper surface of each of thesemiconductor dice 510 and respective ones of the contact pads 504 onthe upper surface of the printed circuit board substrate 502. In oneembodiment, conventional wire bonding machinery connects first ends ofthe wires 518 to respective ones of the contact pads 504 on the uppersurface of the printed circuit board substrate 502 and then connectsrespective second ends of the wires 518 to a respective one of the atleast one contact pad 514 on the upper surfaces of the semiconductordice 510. Additionally, a plurality of conventional lenses 520 is placedover the sensor areas 512 of the semiconductor dice 510. For example,pick-and-place machinery employing conventional surface mount technologymay be used to place each of the lenses 520 on the upper surface of oneof the semiconductor dice 510. A conventional transparent adhesivematerial 522 secures each of the lenses 520 to a respective one of thesemiconductor dice 510.

Each of the lenses 520 and/or the transparent adhesive material 522 mayenable most, if not all, of the light incident on the lenses 520 and/orthe transparent adhesive material 522 to pass therethrough. For example,the lenses 520 and/or the transparent adhesive material 522 may enableat least 85% of the light in the visible spectrum or light in theinfrared spectrum that is incident on the lenses 520 and/or thetransparent adhesive material 522 to pass therethrough. Additionally oralternatively, the lenses 520 and/or the transparent adhesive material522 may act as a filter that prevents predetermined wavelengths of lightfrom passing therethrough. For example, the lenses 520 and/or thetransparent adhesive material 522 may prevent light in the visiblespectrum or light in the infrared spectrum that is incident on thelenses 520 and/or the transparent adhesive material 522 from passingtherethrough.

As shown in FIG. 5D, a plurality of masks 524 is positioned over thelenses 520 that are disposed over the sensor areas 512 of thesemiconductor dice 510. In addition, a plurality of masks 526 ispositioned over the lenses 302 of the light emitting assemblies 300. Inone embodiment, a conventional adhesive material (not shown) secures themasks 524 to the lenses 520 and also secures the masks 526 to the lenses302.

An encapsulating layer 528 is formed on the upper surface of the printedcircuit board substrate 502 and upper and side surfaces of each of thesemiconductor dice 510, the wires 518, the lenses 520, and the lenses302, and on side surfaces of the light emitting assemblies 300. Theencapsulating layer 528 is formed from a conventional molding compoundthat does not transmit light therethrough. For example, theencapsulating layer 528 may be formed from a black material. Initially,the encapsulating layer 528 may be in a liquid or gel form and may bepoured or injected over the printed circuit board substrate 502, thesemiconductor dice 510, the wires 518, the lenses 520, and the lightemitting assemblies 300. The encapsulating layer 528 may then be curedwith UV light, heat, and/or moisture to cause the encapsulating layer528 to take a solid form more quickly. Preferably, the temperature atwhich the molding compound forming the encapsulating layer 528transitions from a solid form to a liquid or gel form is lower than thetemperature at which the transparent material 220 forming the lenses 302of the light emitting assemblies 300 transitions from a solid form to aliquid or gel form. Thus, the semiconductor assembly 500 may be at atemperature that enables the encapsulating layer 528 to be in a liquidor gel form while the transparent material 220 forming the lenses 302 ofthe light emitting assemblies 300 remains in a solid form.

As shown in FIG. 5E, the masks 524 are then removed from the lenses 520over the sensor areas 512 of the semiconductor dice 510, and the masks526 are removed from the lenses 302 of the light emitting assemblies300. When the masks 524 and the masks 526 are removed, first apertures530 are formed over respective lenses 302 of the light emittingassemblies 300 and second apertures 532 are formed over respectivelenses 520 over the sensor areas 512 of the semiconductor dice 510. Inone embodiment, blades are used to scrape or otherwise remove portionsof the encapsulating layer 528 from the upper surfaces of the lenses 302of the light emitting assemblies 300 and the lenses 520 over the sensorareas 512 of the semiconductor dice 510 to form the first openings 530and the second openings 532, respectively.

In one embodiment, the masks 524 and the masks 526 are projections thatextend downwardly from an upper surface of a cavity included inconventional film-assisted molding machinery. The semiconductor assembly500 is placed in the cavity and the machinery raises the semiconductorassembly 500 toward the upper surface of the cavity until the masks 524and the masks 526 contact the upper surfaces of the lenses 302 of thelight emitting assemblies 300 and the lenses 520 over the sensor areas512 of the semiconductor dice 510, respectively. While the machineryholds the semiconductor assembly 500 in this position, the machineryinjects the molding compound that forms the encapsulating layer 528 intothe cavity. After the molding compound has at least partially cured orhardened, the machinery moves the semiconductor assembly 500 away fromthe upper surface of the cavity until the masks 524 and the masks 526 nolonger contact the lenses 302 of the light emitting assemblies 300 andthe lenses 520 over the sensor areas 512 of the semiconductor dice 510,respectively.

With reference to FIGS. 5E, 6A, and 6B, the semiconductor assembly 500is then sawed or otherwise separated to form a plurality of proximitysensors 600. For example, the blade of a saw is placed on the uppersurface of the encapsulating layer 528 at the location 534 in FIG. 5Eand then moved downwardly until the blade passes through theencapsulating layer 528 and the printed circuit board substrate 502 toform a plurality of proximity sensors 600.

FIG. 6A is a top plan view of the proximity sensor 600. The proximitysensor 600 includes a cover 602 formed from the encapsulating layer 528.The cover 602 has a first aperture 604 and a second aperture 606 formedtherein. The first aperture 604 is formed from one of the firstapertures 530 and the second aperture 606 is formed from one of thesecond apertures 532.

FIG. 6B is a cross-sectional view of the proximity sensor 600 along theline 6B-6B shown in FIG. 6A. The proximity sensor 600 includes theprinted circuit board substrate 502. An upper surface of the printedcircuit board substrate 502 includes the contact pads 504. A lowersurface of the printed circuit board substrate 502 includes the contactpads 506. The conductive traces 508 form electrical connections betweenone or more of the contact pads 504 on the upper surface of the printedcircuit board substrate 502 and one or more of the contact pads 506 onthe lower surface of the printed circuit board substrate 502.

The semiconductor die 510 is disposed on the upper surface of theprinted circuit board substrate 502. The upper surface of thesemiconductor die 510 includes the sensor area 512 and the at least onecontact pad 514. The conductive adhesive material 516 forms anelectrical connection between a lower surface of the semiconductor die510 and one of the contact pads 504 on the upper surface of the printedcircuit board substrate 502. The conductive adhesive material 516 alsoforms an electrical connection between each of the contact pads 206 onthe lower surface of the printed circuit board substrate 202 of thelight emitting assembly 300 and a respective one of the contact pads 504on the upper surface of the printed circuit board substrate 502.

At least one wire 518 forms an electrical connection between at leastone of the contact pads 504 on the upper surface of the printed circuitboard substrate 502 and the at least one contact pad 514 on the uppersurface of the semiconductor die 510. The lens 520 disposed over thesensor area 512 of the semiconductor die 510. The transparent adhesivematerial 522 secures the lens 520 to the semiconductor die 510. Theproximity sensor 600 also includes the light emitting assembly 300,which is described above.

Because the cover 602 is formed from an opaque material, the cover 602prevents external light from reaching the sensor area 512 of thesemiconductor die 510. Additionally, the cover 602 prevents lightemitted from the light emitting device 210, which does not exit theproximity sensor 600 through the first aperture 604 and reenter theproximity sensor through the second aperture 606, from reaching thesensor area 512 of the semiconductor die 510.

During operation of the proximity sensor 600, electrical power isprovided to the proximity sensor 600 through one or more of the contactpads 506 on the lower surface of the printed circuit board substrate502. The electrical power may be supplied to the semiconductor die 510via one or more of the conductive traces 508 connected to one of thecontact pads 504 on the upper surface of the printed circuit boardsubstrate 502 that is connected by at least one wire 518 to at least onecontact pad 514 on the upper surface of the semiconductor die 510. Acommon reference potential (e.g., ground) may be provided to theproximity sensor 600 through one or more of the contact pads 506 on thelower surface of the printed circuit board substrate 502. The commonreference potential may be supplied to the semiconductor die 510 via oneor more of the conductive traces 508 connected to one of the contactpads 504 on the upper surface of the printed circuit board substrate 502that is connected to the lower surface of the semiconductor die 510.

Additionally, the electrical power and the common reference potentialmay be supplied to the light emitting assembly 300 via two or more ofthe conductive traces 508 connected to two of the contact pads 504 onthe upper surface of the printed circuit board substrate 502 that areconnected to respective ones of the contact pads 206 on the lowersurface of the printed circuit board substrate 202. The proximity sensor600 may provide data or control signals from one or more of the contactpads 506 on the lower surface of the printed circuit board substrate502. Those contact pads 506 are connected by one or more of theconductive traces 508 to one or more of the contact pads 504 on theupper surface of the printed circuit board substrate 502 that also areconnected by one or more of the wires 518 to one or more of the contactpads 514 on the upper surface of the semiconductor die 510. Only onesuch contact pad 504, contact pad 514, and wire 518 is shown in FIG. 6B.

The light emitting device 210 emits light through the lens 302 and thefirst aperture 604 in the cover 602. Light that is reflected by anobject in the vicinity of the proximity sensor 600 may enter the secondaperture 606 in the cover 602, pass through the lens 520, and impact thesensor area 512 of the semiconductor die 510. The semiconductor die 510outputs one or more signals that are indicative of or proportional tothe magnitude of the intensity of the light incident on the sensor area512, from one or more of the contact pads 514 on the upper surface ofthe semiconductor die 510. The semiconductor die 510 may include adriver that causes power to be supplied to the light emitting assembly300 at predetermined times.

FIG. 7A is a top plan view of a proximity sensor 700, according to oneembodiment. FIG. 7B is a cross-sectional view of the proximity sensor700 along the line 7B-7B shown in FIG. 7A. The proximity sensor 700 issimilar to the proximity sensor 600 shown in FIGS. 6A and 6B, exceptthat the proximity sensor 700 includes an additional lens over the lightemitting assembly, as explained in detail below.

The proximity sensor 700 includes a cover 702 having a first aperture704 and a second aperture 706 formed therein. The proximity sensor 700also includes a printed circuit board substrate 708. An upper surface ofthe printed circuit board substrate 708 includes a plurality of contactpads 710. A lower surface of the printed circuit board substrate 708includes a plurality of contact pads 712. A plurality conductive traces714 form electrical connections between one or more of the contact pads710 on the upper surface of the printed circuit board substrate 708 andone or more of the contact pads 712 on the lower surface of the printedcircuit board substrate 708.

A conventional semiconductor die 716 is disposed on the upper surface ofthe printed circuit board substrate 708. The semiconductor die 716includes a sensor area 718 and at least one contact pad 720 on an uppersurface of the semiconductor die 716. In one embodiment, the sensor area718 is part of a photodiode that converts light into current, whereinthe magnitude of the current is proportional to the magnitude of theintensity of the light.

A conventional conductive adhesive material 722 forms an electricalconnection between a lower surface of the semiconductor die 716 and oneof the contact pads 710 on the upper surface of the printed circuitboard substrate 708. The conductive adhesive material 722 also forms anelectrical connection between each of the contact pads 206 on the lowersurface of the printed circuit board substrate 202 and a respective oneof the contact pads 710 on the upper surface of the printed circuitboard substrate 708.

At least one wire 724 forms at least one electrical connection betweenat least one of the contact pads 710 on the upper surface of the printedcircuit board substrate 708 and the at least one contact pad 720 on theupper surface of the semiconductor die 716.

A conventional lens 726 is disposed over the sensor area 718 of thesemiconductor die 716. A transparent adhesive material 728 secures thelens 726 to the semiconductor die 716. A lens 730 is disposed over thelens 302 of the light emitting assembly 300. A transparent adhesivematerial 732 secures the lens 730 to the lens 302 of the light emittingassembly 300.

The lens 726, the transparent adhesive material 728, the lens 730 and/orthe transparent adhesive material 732 may enable most, if not all, ofthe light incident thereon to pass therethrough. For example, the lens726, the transparent adhesive material 728, the lens 730 and/or thetransparent adhesive material 732 may enable at least 85% of the lightin the visible spectrum or light in the infrared spectrum that isincident thereon to pass therethrough. Additionally or alternatively,the lens 726, the transparent adhesive material 728, the lens 730 and/orthe transparent adhesive material 732 may act as a filter that preventspredetermined wavelengths of light from passing therethrough. Forexample, the lens 726, the transparent adhesive material 728, the lens730 and/or the transparent adhesive material 732 may prevent light inthe visible spectrum or light in the infrared spectrum that is incidentthereon from passing therethrough.

During fabrication of the proximity sensor 700, masks (not shown) areplaced over at least part of the upper surfaces of the lens 726 and thelens 730. An encapsulation layer that forms the cover 702 is placed onthe upper surface of the printed circuit board substrate 708 and atleast part of the upper and side surfaces each of the semiconductor die716, the wire 724, the lens 726, and the lens 730, and on the sidesurfaces of the light emitting assembly 300. The masks are then removedto form the first aperture 704 and the second aperture 706.

FIG. 8A is a top plan view of a proximity sensor 800, according to oneembodiment. FIG. 8B is a cross-sectional view of the proximity sensor800 take along the line 8B-8B shown in FIG. 8A. The proximity sensor 800is similar to the proximity sensor 600 shown in FIGS. 6A and 6B, exceptthat the light emitting assembly is mounted on the semiconductor die, asexplained in detail below.

The proximity sensor 800 includes a cover 802 having a first aperture804 and a second aperture 806 formed therein. The proximity sensor 800also includes a printed circuit board substrate 808. An upper surface ofthe printed circuit board substrate 808 includes a plurality of contactpads 810. A lower surface of the printed circuit board substrate 808includes a plurality of contact pads 812. A plurality conductive traces814 form electrical connections between one or more of the contact pads810 on the upper surface of the printed circuit board substrate 808 andone or more of the contact pads 812 on the lower surface of the printedcircuit board substrate 808.

A conventional semiconductor die 816 is disposed on the upper surface ofthe printed circuit board substrate 808. The semiconductor die 816includes a sensor area 818 and a plurality of contact pads 820 on anupper surface of the semiconductor die 816. In one embodiment, thesensor area 818 is part of a photodiode that converts light intocurrent, wherein the magnitude of the current is proportional to themagnitude of the intensity of the light.

A conventional conductive adhesive material 822 forms an electricalconnection between a lower surface of the semiconductor die 816 and oneof the contact pads 810 on the upper surface of the printed circuitboard substrate 808. At least one wire 824 forms an electricalconnection between at least one of the contact pads 810 on the uppersurface of the printed circuit board substrate 808 and at least one thecontact pads 820 on the upper surface of the semiconductor die 816.

A conventional lens 826 is disposed over the sensor area 818 of thesemiconductor die 816. A conventional transparent adhesive material 828secures the lens 826 to the semiconductor die 816. The lenses 826 and/orthe transparent adhesive material 828 may enable most, if not all, ofthe light incident thereon to pass therethrough. For example, the lenses826 and/or the transparent adhesive material 828 may enable at least 85%of the light in the visible spectrum or light in the infrared spectrumthat is incident thereon to pass therethrough. Additionally oralternatively, the lenses 826 and/or the transparent adhesive material828 may act as a filter that prevents predetermined wavelengths of lightfrom passing therethrough. For example, the lenses 826 and/or thetransparent adhesive material 828 may prevent light in the visiblespectrum or light in the infrared spectrum that is incident thereon frompassing therethrough.

The proximity sensor 800 also includes the light emitting assembly 300,which is described above. The conductive adhesive material 822 forms anelectrical connection between each of the contact pads 206 on the lowersurface of the printed circuit board substrate 202 and a respective oneof the contact pads 820 on the upper surface of the semiconductor die816. During fabrication of the proximity sensor 800, masks (not shown)are placed over at least part of the upper surfaces of the lens 826 andthe lens 302. An encapsulation layer that forms the cover 802 is placedon the upper surface of the printed circuit board substrate 808 and atleast part of the upper and side surfaces each of the semiconductor die816, the wire 824, the lens 826, and the light emitting assembly 830.The masks are then removed to form the first aperture 804 and the secondaperture 806.

FIG. 9A is a top plan view of a proximity sensor 900, according to oneembodiment. FIG. 9B is a cross-sectional view of the proximity sensor900 take along the line 9B-9B shown in FIG. 9A. The proximity sensor 900is similar to the proximity sensor 800 shown in FIGS. 8A and 8B, exceptthat an additional lens is mounted on the light emitting assembly, asexplained in detail below.

The proximity sensor 900 includes a cover 902 having a first aperture904 and a second aperture 906 formed therein. The proximity sensor 900also includes a printed circuit board substrate 908. An upper surface ofthe printed circuit board substrate 908 includes a plurality of contactpads 910. A lower surface of the printed circuit board substrate 908includes a plurality of contact pads 912. A plurality conductive traces914 forms electrical connections between one or more of the contact pads910 on the upper surface of the printed circuit board substrate 908 andone or more of the contact pads 912 on the lower surface of the printedcircuit board substrate 908.

A conventional semiconductor die 916 is disposed on the upper surface ofthe printed circuit board substrate 908. The semiconductor die 916includes a sensor area 918 and a plurality of contact pads 920 on anupper surface of the semiconductor die 916. In one embodiment, thesensor area 918 is part of a photodiode that converts light intocurrent, wherein the magnitude of the current is proportional to themagnitude of the intensity of the light.

A conventional conductive adhesive material 922 forms an electricalconnection between a lower surface of the semiconductor die 916 and oneof the contact pads 910 on the upper surface of the printed circuitboard substrate 908. At least one wire 924 forms an electricalconnection between at least one of the contact pads 910 on the uppersurface of the printed circuit board substrate 908 and at least one thecontact pads 920 on the upper surface of the semiconductor die 916.

A conventional lens 926 is disposed over the sensor area 918 of thesemiconductor die 916. A conventional transparent adhesive material 928secures the lens 926 to the semiconductor die 916. The proximity sensor900 also includes the light emitting assembly 300, which is describedabove. The conductive adhesive material 922 forms an electricalconnection between each of the contact pads 206 on the lower surface ofthe printed circuit board substrate 202 and a respective one of thecontact pads 820 on the upper surface of the semiconductor die 916. Alens 930 is disposed over the lens 302 of the light emitting assembly300. A transparent adhesive material 932 secures the lens 930 to thelens 302 of the light emitting assembly 300.

The lens 926, the transparent adhesive material 928, the lens 930 and/orthe transparent adhesive material 932 may enable most, if not all, ofthe light incident thereon to pass therethrough. For example, the lens926, the transparent adhesive material 928, the lens 930 and/or thetransparent adhesive material 932 may enable at least 85% of the lightin the visible spectrum or light in the infrared spectrum that isincident thereon to pass therethrough. Additionally or alternatively,the lens 926, the transparent adhesive material 928, the lens 930 and/orthe transparent adhesive material 932 may act as a filter that preventspredetermined wavelengths of light from passing therethrough. Forexample, the lens 926, the transparent adhesive material 928, the lens930 and/or the transparent adhesive material 932 may prevent light inthe visible spectrum or light in the infrared spectrum that is incidentthereon from passing therethrough.

During fabrication of the proximity sensor 900, masks (not shown) areplaced over at least part of the upper surfaces of the lens 926 and thelens 903. An encapsulation layer that forms the cover 902 is placed onthe upper surface of the printed circuit board substrate 908 and atleast part of the upper and side surfaces each of the semiconductor die916, the wire 924, the lens 926, and the lens 930, and side surfaces ofthe light emitting assembly 300. The masks are then removed to form thefirst aperture 904 and the second aperture 906.

FIG. 10A is a top plan view of a proximity sensor 1000, according to oneembodiment. FIG. 10B is a cross-sectional view of the proximity sensor1000 along the line 10B-10B shown in FIG. 10A. The proximity sensor 1000is similar to the proximity sensor 600 shown in FIGS. 6A and 6B, exceptthat the light emitting assembly does not include a printed circuitboard substrate and the light emitting device includes a plurality ofcontact pads on a lower surface thereof, as explained in detail below.

The proximity sensor 1000 includes a cover 1002 having a first aperture1004 and a second aperture 1006 formed therein. The proximity sensor1000 also includes a printed circuit board substrate 1008. An uppersurface of the printed circuit board substrate 1008 includes a pluralityof contact pads 1010. A lower surface of the printed circuit boardsubstrate 1008 includes a plurality of contact pads 1012. A pluralityconductive traces 1014 form electrical connections between one or moreof the contact pads 1010 on the upper surface of the printed circuitboard substrate 1008 and one or more of the contact pads 1012 on thelower surface of the printed circuit board substrate 1008.

A conventional semiconductor die 1016 is disposed on the upper surfaceof the printed circuit board substrate 1008. The semiconductor die 1016includes a sensor area 1018 and at least one contact pad 1020 on anupper surface of the semiconductor die 1016. In one embodiment, thesensor area 1018 is part of a photodiode that converts light intocurrent, wherein the magnitude of the current is proportional to themagnitude of the intensity of the light.

A conventional conductive adhesive material 1022 forms an electricalconnection between a lower surface of the semiconductor die 1016 and oneof the contact pads 1010 on the upper surface of the printed circuitboard substrate 1008. At least one wire 1024 forms an electricalconnection between at least one of the contact pads 1010 on the uppersurface of the printed circuit board substrate 1008 and the at least onecontact pads 1020 on the upper surface of the semiconductor die 1016.

A conventional lens 1026 is disposed over the sensor area 1018 of thesemiconductor die 1016. A conventional transparent adhesive material1028 secures the lens 1026 to the semiconductor die 1016. The proximitysensor 1000 also includes a light emitting assembly 1030. The lightemitting assembly 1030 includes a conventional light emitting device1032. In one embodiment, the light emitting device 1032 is aconventional light emitting diode (LED). In one embodiment, the lightemitting device 1032 is a conventional vertical-cavity surface-emittinglaser (VCSEL).

A lower surface of the light emitting device 1032 includes a pluralityof contact pads 1034. A conventional lens 1036 is disposed over a lightemitting area of the light emitting device 1032. A conventionaltransparent adhesive material 1038 secures the lens 1036 to the lightemitting device 1032.

The conventional lens 1026, the transparent adhesive material 1028, thelens 1036, and/or the transparent adhesive material 1038 may enablemost, if not all, of the light incident thereon to pass therethrough.For example, the lens 1026, the transparent adhesive material 1028, thelens 1036 and/or the transparent adhesive material 1038 may enable atleast 85% of the light in the visible spectrum or light in the infraredspectrum that is incident thereon to pass therethrough. Additionally oralternatively, the lens 1026, the transparent adhesive material 1028,the lens 1036, and/or the transparent adhesive material 1038 may act asa filter that prevents predetermined wavelengths of light from passingtherethrough. For example, the lens 1026, the transparent adhesivematerial 1028, the lens 1036, and/or the transparent adhesive material1038 may prevent light in the visible spectrum or light in the infraredspectrum that is incident thereon from passing therethrough.

A plurality of solder bumps 1040 form electrical connections between thecontact pads 1034 and respective ones of the contact pads 1010 formed onthe upper surface of the printed circuit board substrate 1008. Forexample, during fabrication of the proximity sensor 1000, the solderbumps 1040 are formed on the contact pads 1034 that are on the lowersurface of light emitting device 1032. The light emitting assembly 1030is then placed over the upper surface of the printed circuit boardsubstrate 1008, the solder bumps 1040 are aligned with correspondingcontact pads 1010 on the upper surface of the printed circuit boardsubstrate 1008, and the solder bumps 1040 are placed onto thecorresponding contact pads 1010 on the upper surface of the printedcircuit board substrate 1008. The resulting assembly is then heated andthe solder bumps 1040 form electrical connections between the contactpads 1034 on the lower surface of light emitting device 1032 andrespective one of the contact pads 1010 on the upper surface of theprinted circuit board substrate 1008.

Subsequently, masks (not shown) are placed over at least part of theupper surfaces of the lens 1026 and the lens 1036. An encapsulationlayer that forms the cover 1002 is placed on the upper surface of theprinted circuit board substrate 1008 and at least part of the upper andside surfaces each of the semiconductor die 1016, the wire 1024, thelens 1026, and the lens 1036, and on the side surfaces of the lightemitting assembly 1030. The masks are then removed to form the firstaperture 1004 and the second aperture 1006.

FIG. 11A is a top plan view of a proximity sensor 1100, according to oneembodiment. FIG. 11B is a cross-sectional view of the proximity sensor1100 take along the line 11B-11B shown in FIG. 11A. The proximity sensor1100 is similar to the proximity sensor 1000 shown in FIGS. 10A and 10B,except that the light emitting assembly is mounted on the semiconductordie, as explained in detail below.

The proximity sensor 1100 includes a cover 1102 having a first aperture1104 and a second aperture 1106 formed therein. The proximity sensor1100 also includes a printed circuit board substrate 1108. An uppersurface of the printed circuit board substrate 1108 includes a pluralityof contact pads 1110. A lower surface of the printed circuit boardsubstrate 1108 includes a plurality of contact pads 1112. A pluralityconductive traces 1114 form electrical connections between one or moreof the contact pads 1110 on the upper surface of the printed circuitboard substrate 1108 and one or more of the contact pads 1112 on thelower surface of the printed circuit board substrate 1108.

A conventional semiconductor die 1116 is disposed on the upper surfaceof the printed circuit board substrate 1108. The semiconductor die 1116includes a sensor area 1118 and a plurality of contact pads 1120 on anupper surface of the semiconductor die 1116. In one embodiment, thesensor area 1118 is part of a photodiode that converts light intocurrent, wherein the magnitude of the current is proportional to themagnitude of the intensity of the light.

A conductive adhesive material 1122 forms an electrical connectionbetween a lower surface of the semiconductor die 1116 and one of thecontact pads 1110 on the upper surface of the printed circuit boardsubstrate 1108. At least one wire 1124 forms an electrical connectionbetween at least one of the contact pads 1110 on the upper surface ofthe printed circuit board substrate 1108 and at least one the contactpads 1120 on the upper surface of the semiconductor die 1116.

A conventional lens 1126 is disposed over the sensor area 1118 of thesemiconductor die 1116. A conventional transparent adhesive material1128 secures the lens 1126 to the semiconductor die 1116. The proximitysensor 1100 also includes a light emitting assembly 1130. The lightemitting assembly 1130 includes a conventional light emitting device1132. In one embodiment, the light emitting device 1132 is aconventional light emitting diode (LED). In one embodiment, the lightemitting device 1132 is a conventional vertical-cavity surface-emittinglaser (VCSEL).

A lower surface of the light emitting device 1132 includes a pluralityof contact pads 1134. A conventional lens 1136 is disposed over a lightemitting area of the light emitting device 1132. A conventionaltransparent adhesive material 1138 secures the lens 1136 to the lightemitting device 1132.

The lens 1126, the transparent adhesive material 1128, the lens 1136,and/or the transparent adhesive material 1138 may enable most, if notall, of the light incident thereon to pass therethrough. For example,the lens 1126, the transparent adhesive material 1128, the lens 1136,and/or the transparent adhesive material 1138 may enable at least 85% ofthe light in the visible spectrum or light in the infrared spectrum thatis incident thereon to pass therethrough. Additionally or alternatively,the lens 1126, the transparent adhesive material 1128, the lens 1136,and/or the transparent adhesive material 1138 may act as a filter thatprevents predetermined wavelengths of light from passing therethrough.For example, the lens 1126, the transparent adhesive material 1128, thelens 1136, and/or the transparent adhesive material 1138 may preventlight in the visible spectrum or light in the infrared spectrum that isincident thereon from passing therethrough.

A plurality of solder bumps 1140 form electrical connections withrespective ones of the contact pads 1120 on the upper surface of thesemiconductor die 1116. For example, during fabrication of the proximitysensor 1100, the solder bumps 1140 are formed on the contact pads 1134that are on the lower surface of light emitting device 1132. The lightemitting assembly 1130 is then placed over the upper surface of thesemiconductor die 1116, the solder bumps 1140 are aligned withcorresponding contact pads 1120 on the upper surface of thesemiconductor die 1116, and the solder bumps 1140 are placed onto thecorresponding contact pads 1120 on the upper surface of semiconductordie 1116. The resulting assembly is then heated and the solder bumps1140 form electrical connections between the contact pads 1134 on thelower surface of light emitting device 1132 and respective ones of thecontact pads 1120 on the upper surface of the semiconductor die 1116.

Subsequently, masks (not shown) are placed over at least part of theupper surfaces of the lens 1126 and the lens 1136. An encapsulationlayer that forms the cover 1102 is placed on the upper surface of theprinted circuit board substrate 1108 and at least part of the upper andside surfaces each of the semiconductor die 1116, the wire 1124, thelens 1126, and the lens 1136, and on the side surfaces of the lightemitting assembly 1130. The masks are then removed to form the firstaperture 1104 and the second aperture 1106.

FIGS. 12A-12H show a proximity sensor cap assembly 1200 at variousstages of fabrication, according to one embodiment.

As shown in FIG. 12A, a carrier 1202 is provided. An adhesion layer 1204is formed over an upper surface of the carrier 1202. For example, thecarrier 1202 can be a silicon or a glass substrate or a metal sheet, andthe adhesion layer 1204 is formed from a conventional adhesive material.

As shown in FIG. 12B, a plurality of conventional lenses 1206 is placedon the adhesion layer 1204. For example, pick-and-place machineryemploying conventional surface mount technology may be used to place thelenses 1206 on the adhesion layer 1204. The lenses 1206 may be formedfrom glass or plastic, for example. The lenses 1206 may enable most, ifnot all, of the light incident thereon to pass therethrough. Forexample, the lenses 1206 may enable at least 85% of the light in thevisible spectrum (e.g., wavelengths of light from approximately 1400nanometers to 700 nanometers) or light in the infrared spectrum (e.g.,wavelengths of light from approximately 700 nanometers to 1250nanometers) that is incident thereon to pass therethrough. Additionallyor alternatively, the lenses 1206 may act as a filter that preventspredetermined wavelengths of light from passing therethrough. Forexample, the lenses 1206 may prevent light in the visible spectrum orlight in the infrared spectrum that is incident thereon from passingtherethrough.

Each of the lenses 1206 includes a first side 1208, a second side 1210,and at least one third side 1212. The first side 1208 of each of thelenses 1206 faces the adhesion layer 1204. The second side 1210 of eachof the lenses 1206 faces away from the adhesion layer 1204. Each thirdside 1212 is disposed between the first side 1208 and the second side1210 of one of the lenses 1206. A plurality of surfaces respectivelycorresponds to the first side 1208, the second side 1210, and the thirdside 1212 of each of the lenses 1206.

As shown in FIG. 12C, in one embodiment a plurality of masks 1214 isplaced over the carrier 1202. Each mask 1214 is placed on the secondside 1210 of one of the lenses 1206. For example, pick-and-placemachinery employing conventional surface mount technology may be used toplace the masks 1214 on the lenses 1206. An adhesive material (notshown) may be used to secure the masks 1214 to the lenses 1206. Anencapsulating layer 1216 is then formed on exposed portions of theadhesion layer 1204, the third sides 1212 of the lenses 1206, andexposed portions of the second sides 1210 of the lenses 1206 that arenot covered by the masks 1214. The encapsulating layer 1216 includes afirst side 1218 that is in contact with the adhesion layer 1204 and asecond side 1220 that faces away from the adhesion layer 1204 and iscontact with the second side 1210 of each of the lenses 1206. Each ofthe first side 1218 and the second side 1220 of the encapsulating layer1216 corresponds to at least one surface.

The masks 1214 shown in FIG. 12C are optional. In another embodiment,the masks 1214 shown in FIG. 12C are not used. A mold cavity is usedinstead. The areas shown covered by the masks 1214 are left open and theproximity sensor cap assembly 1200 is placed in the mold cavity. Themold cavity is shaped such that the encapsulating layer 1216 is formedas shown in FIG. 12D when the mold cavity is filled with a moldingcompound. Because steps to apply and remove the masks 1214 are notrequired when the cavity mold is used, use of the mold cavity can reducethe number of process steps.

The encapsulating layer is formed from a liquid that is placed onto theset of lenses. It can be a polymer, an epoxy, or other packagingmaterial. It can be injected in a mold, spun on, flowed on, or otherwiseapplied in liquid form, after which it is cured. Since it is applied inliquid form around the lenses and then cured to be hardened, it willstrongly adhere to the lens and be assured of blocking all light inareas around the lens. Layer 1216 is formed of a light blocking, highlyopaque material.

As shown in FIG. 12D, a plurality of apertures 1222 is formed in thesecond side 1220 of encapsulating layer 1216 when the masks 1214 areremoved from the lenses 1206. Each of the apertures 1222 is positionedover one of the lenses 1206.

Next, the encapsulating layer 1216 and the lenses 1206 are separatedfrom the adhesion layer 1204. For example, a lower portion of theproximity sensor cap assembly 1200 that includes the adhesion layer 1204is placed in a solvent such as water to separate the encapsulating layer1216 and the lenses 1206 from the adhesion layer 1204.

In one embodiment, the masks 1214 are projections that extend downwardlyfrom an upper surface of a cavity included in film-assisted moldingmachinery. The proximity sensor cap assembly 1200 is then placed in thecavity and raised toward the upper surface of the cavity until the masks1214 contact the surfaces 1210 of the lenses 1206. While the machineryholds the proximity sensor cap assembly 1200 in this position, themachinery injects the molding compound that forms the encapsulatinglayer 1216 into the cavity. After the molding compound has at leastpartially hardened, the machinery moves the proximity sensor capassembly 1200 away from the upper surface of the cavity until the masks1214 no longer contact the lenses 1206.

As shown in FIG. 12E, the encapsulating layer 1216 and the lenses 1206are then flipped over and placed over a carrier 1224 having an adhesionlayer 1226 formed thereon. For example, the carrier 1224 is a siliconglass or other carrier and the adhesion layer 1226 is formed from aconventional adhesive material. The second side 1220 of theencapsulating layer 1216 is then placed on the adhesion layer 1226. Forexample, pick-and-place machinery employing conventional surface mounttechnology may be used to place the encapsulating layer 1216 on theadhesion layer 1228.

As shown in FIG. 12F, in one embodiment a plurality of masks 1228 isplaced on the first side 1208 of each of the lenses 1206 and portions ofthe first side 1218 of the encapsulating layer 1216. For example,pick-and-place machinery employing conventional surface mount technologymay be used to place the masks 1228 on the lenses 1206 and theencapsulating layer 1216. An adhesive material (not shown) may be usedto secure the masks 1228 to the lenses 1206 and the encapsulating layer1216.

A molding compound is then formed on exposed portions of theencapsulating layer 1216 that are not covered by the masks 1228. Themolding compound forms a first plurality of feet 1230, a secondplurality of feet 1232, and a third plurality of feet 1234 (shown inFIGS. 12G and 12H). As explained below, a pair of the feet 1230 and apair of the feet 1234 form outer walls of a proximity sensor cap, andone of the feet 1232 forms a light barrier within the proximity sensorcap. The molding compound that forms the feet 1230, the feet 1232, andthe feet 1234 is a conventional molding compound that does not transmitlight therethrough. For example, the molding compound may be formed froma black material. The same molding compound may be used to form theencapsulating layer 1216, the feet 1230, the feet 1232, and the feet1234.

As shown in FIG. 12G, the masks 1228 are then removed from the firstside 1208 of each of the lenses 1206 and the portions of the first side1218 of the encapsulating layer 1216. Each of the feet 1230 and the feet1234 has a height of h₁ and each of the feet 1232 has a height of h₂,wherein h₁ is greater than h₂.

The masks 1228 shown in FIG. 12F are optional. In another embodiment,the masks 1228 shown in FIG. 12F are not used. A mold cavity is usedinstead. The areas shown covered by the masks 1228 are left open and theproximity sensor cap assembly 1200 is placed in the mold cavity. Themold cavity is shaped such that the feet 1230, the feet 1232, and thefeet 1234 are formed as shown in FIG. 12G when the mold cavity is filledwith a molding compound. Because steps to apply and remove the masks1228 are not required when the cavity mold is used, use of the moldcavity can reduce the number of process steps.

In one embodiment, the masks 1228 are projections that extend downwardlyfrom an upper surface of a cavity included in film-assisted moldingmachinery. The proximity sensor cap assembly 1200 is then placed in thecavity and raised toward the upper surface of the cavity until the masks1228 contact the surfaces 1208 of the lenses 1206 and portions of thefirst side 1218 of the encapsulating layer 1216. While the machineryholds the proximity sensor cap assembly 1200 in this position, themachinery injects the molding compound that forms the feet 1230, thefeet 1232, and the feet 1234 into the cavity. After the molding compoundhas at least partially hardened, the machinery moves the proximitysensor cap assembly 1200 away from the upper surface of the cavity untilthe masks 1228 no longer contact the lenses 1206 and the encapsulatinglayer 1216.

As shown in FIG. 12H, a blade 1236 of a saw (not shown) cuts or saws atleast one cap foot 1230 in a lengthwise direction of the at least onecap foot 1230. The blade 1236 moves downwardly and passes through the atleast one cap foot 1230 and the encapsulating layer 1216 under the atleast one cap foot 1230. In practice, feet 1230 and 1234 will be acommon wall that forms the outer wall of the proximity sensor cap 1300.

Additionally, the encapsulating layer 1216 is separated from theadhesion layer 1226 to form a plurality of proximity sensor caps 1300(shown in FIGS. 13A and 13B). For example, at least a lower portion ofthe proximity sensor cap assembly 1200 that includes the adhesion layer1226 is placed in a solvent such as water to separate the encapsulatinglayer 1216 from the adhesion layer 1226.

FIG. 13A is a top view of the proximity sensor cap 1300, according toone embodiment. The proximity sensor cap 1300 includes an upper portion1302 formed from the encapsulating layer 1216. The upper portion 1302includes a first aperture 1304 and a second aperture 1306 correspondingto a pair of the apertures 1222.

FIG. 13B is a cross-sectional view of the proximity sensor cap 1300along the line 13B-13B shown in FIG. 13A. The proximity sensor cap 1300includes a pair of first side walls 1308 formed from the cap feet 1230.The proximity sensor cap 1300 also includes a pair of second side walls1310 formed from the cap feet 1234; only one of the side walls 1310 isshown in FIG. 13B. A light blocking member 1312 is formed from one ofthe cap feet 1232. The light blocking member 1312 extends from one ofthe side walls 1310 to an opposing side wall 1310 (not shown). Inaddition, the first side walls 1308 extend from one of the side walls1310 to an opposing side wall 1310 (not shown).

FIG. 14 is a cross-sectional view of a proximity sensor 1400, accordingto one embodiment. The proximity sensor 1400 includes a printed circuitboard substrate 1402. An upper surface of the printed circuit boardsubstrate 1402 includes a plurality of contact pads 1404. A lowersurface of the printed circuit board substrate 1402 includes a pluralityof contact pads 1406. A plurality conductive traces 1408 formselectrical connections between one or more of the contact pads 1404 onthe upper surface of the printed circuit board substrate 1402 and one ormore of the contact pads 1406 on the lower surface of the printedcircuit board substrate 1402.

A conventional semiconductor die 1410 is disposed on the upper surfaceof the printed circuit board substrate 1402. An upper surface of thesemiconductor die 1410 includes a sensor area 1412 and at least onecontact pad 1414. A conventional conductive adhesive material 1416 formsan electrical connection between a lower surface of the semiconductordie 1410 and one of the contact pads 1404 on the upper surface of theprinted circuit board substrate 1402. The conductive adhesive material1416 also secures the semiconductor die 1410 to the printed circuitboard substrate 1402. At least one wire 1418 forms at least oneelectrical connection between at least one of the contact pads 1404 onthe upper surface of the printed circuit board substrate 1402 and the atleast contact pad 1414 on the upper surface of the semiconductor die1410. In one embodiment, conventional wire bonding machinery connectsone end of the at least one wire 818 to one of the contact pads 1404 onthe upper surface of the printed circuit board substrate 1402 and thenconnects the other end of the wire 1418 to one of the at least onecontact pad 1414 on the upper surface of the semiconductor die 1410.

A conventional light emitting device 1420 is disposed on one of thecontact pads 1404 on the upper surface of the printed circuit boardsubstrate 1402. In one embodiment, the light emitting device 1420 is aconventional light emitting diode (LED). In one embodiment, the lightemitting device 1420 is a conventional vertical-cavity surface-emittinglaser (VCSEL). The conductive adhesive material 1416 forms an electricalconnection between a lower surface of the light emitting device 1420,which may include a contact pad, and the contact pad 1404 on the uppersurface of the printed circuit board substrate 1402. The conductiveadhesive material 1416 also secures the light emitting device 1420 tothe printed circuit board substrate 1402.

An upper surface of the light emitting device 1420 includes a lightemitting area 1422 and a contact pad 1424. A wire 1426 forms anelectrical connection between the contact pad 1424 and one of thecontact pads 1404 on the upper surface of the printed circuit boardsubstrate 1402. In one embodiment, conventional wire bonding machineryconnects one end of the wire 1426 to one of the contact pads 1404 on theupper surface of the printed circuit board substrate 1402 and thenconnects the other end of the wire 1418 to the contact pad 1424 on theupper surface of the printed circuit board substrate 1402.

The proximity sensor 1400 also includes the proximity sensor cap 1300shown in FIGS. 13A and 13B. The proximity sensor cap 1300 is secured tothe printed circuit board substrate 1402 and the semiconductor die 1410.More particularly, an adhesive material 1428 a secures the first sidewalls 1308 to the upper surface of the printed circuit board substrate1402. An adhesive material 1428 b secures the second side walls 1310(only one shown in FIG. 14) to the upper surface of the printed circuitboard substrate 1402. Additionally, an adhesive material 1428 c securesthe light blocking member 1312 to an upper surface of the semiconductordie 1410.

The lower surfaces of the first side walls 1308 and the second sidewalls 1310 are flat. The upper surface of the printed circuit boardsubstrate 1402 also is flat. The adhesive material 1428 a and theadhesive material 1428 b do not permit light to pass therethrough. Whenthe proximity sensor cap 1300 is secured to the printed circuit boardsubstrate 1402, the upper portion 1302, the first side walls 1308, andthe second side walls 1310 prevent external light from entering theproximity sensor 1400, other than light that passes through the lenses1206.

In addition, the lower surface of the light blocking member 1312 and theupper surface of the semiconductor die 1410 are flat. The adhesivematerial 1428 c does not permit light to pass therethrough. When theproximity sensor cap 1300 is secured to the printed circuit boardsubstrate 1402 and the semiconductor die 1410, the light blocking member1312 prevents light emitted by the light emitting device 1420 fromreaching the sensor area 1412 of the semiconductor die 1410, other thanlight that exits the first aperture 1304, that is reflected by an objectin the vicinity of the proximity sensor 1400, and that enters the secondaperture 1306.

During operation of the proximity sensor 1400, electrical power isprovided to the proximity sensor 1400 through one or more of the contactpads 1406 on the lower surface of the printed circuit board substrate1402. The electrical power may be supplied to the semiconductor die 1410via one or more of the conductive traces 1408 connected to one of thecontact pads 1404 on the upper surface of the printed circuit boardsubstrate 1402 that is connected by at least one wire 1418 to at leastone contact pad 1414 on the upper surface of the semiconductor die 1410.A common reference potential (e.g., ground) may be provided to theproximity sensor 1400 through one or more of the contact pads 1406 onthe lower surface of the printed circuit board substrate 1402. Thecommon reference potential may be supplied to the semiconductor die 1410via one or more of the conductive traces 1408 connected to one of thecontact pads 1404 on the upper surface of the printed circuit boardsubstrate 1402 that is connected to the lower surface of thesemiconductor die 1410, which may include a contact pad.

Additionally, electrical power is supplied to the light emitting device1420 via one of the contact pads 1404 on the upper surface of theprinted circuit board substrate 1402, which is connected to the contactpad 1424 on the upper surface of the light emitting device 1420. Thecommon reference potential is supplied to the light emitting device 1420via the lower surface of the light emitting device 1420, which mayinclude a contact pad that is coupled to one of the contact pads 1404 onthe upper surface of the printed circuit board substrate 1402.

The proximity sensor 1400 provides data and/or control signals from oneor more of the contact pads 1406 on the lower surface of the printedcircuit board substrate 1402. Those contact pads 1406 are connected byone or more of the conductive traces 1408 to one or more of the contactpads 1404 on the upper surface of the printed circuit board substrate1402, which also are connected by the at least one wire 1418 to at leastone of the contact pads 1414 on the upper surface of the semiconductordie 1410. Only one such contact pad 1404, contact pad 1414, and wire1418 is shown in FIG. 14B.

The light emitting device 1420 emits light through a first lens 1206 andthe first aperture 1304 in the cover 1302. Light that is reflected by anobject in the vicinity of the proximity sensor 1400 may enter the secondaperture 1306 in the cover 1302, pass through a second lens 1206, andimpact the sensor area 1412 of the semiconductor die 1410. Thesemiconductor die 1410 outputs one or more signals that are indicativeof or proportional to the magnitude of the intensity of the lightincident on the sensor area 1412, from the at least one contact pad 1414on the upper surface of the semiconductor die 1410. The semiconductordie 1410 may include a driver that causes power to be supplied to thelight emitting device 1420 at predetermined times.

The various embodiments described above can be combined to providefurther embodiments. All of the U.S. patents, U.S. patent applicationpublications, U.S. patent applications, foreign patents, foreign patentapplications and non-patent publications referred to in thisspecification and/or listed in the Application Data Sheet areincorporated herein by reference, in their entirety. Aspects of theembodiments can be modified, if necessary to employ concepts of thevarious patents, applications and publications to provide yet furtherembodiments.

These and other changes can be made to the embodiments in light of theabove-detailed description. In general, in the following claims, theterms used should not be construed to limit the claims to the specificembodiments disclosed in the specification and the claims, but should beconstrued to include all possible embodiments along with the full scopeof equivalents to which such claims are entitled. Accordingly, theclaims are not limited by the disclosure.

The invention claimed is:
 1. A proximity sensor, comprising: anencapsulating layer having a first side and a second side; a pluralityof cap feet in contact with and extending from the first side of theencapsulating layer, the plurality of cap feet and the encapsulatinglayer being formed from a same material, two of the cap feet having afirst height with respect to the first side of the encapsulating layer,and one of the cap feet having a second height with respect to the firstside of the encapsulating layer, the second height being different fromthe first height; and a plurality of lenses, each of the lenses having afirst side and a second side, the encapsulating layer in contact withthe first side and the second side of each of the lenses; a lightemitting device disposed below a first one of the lenses; asemiconductor die including a sensor area disposed below a second one ofthe lenses; and an adhesive material, which prevents light from passingtherethrough, that secures the one of the cap feet having the secondheight with respect to the first side of the encapsulating layer to thesemiconductor die.
 2. The proximity sensor of claim 1 wherein theencapsulating layer is at least partially disposed over each of thelenses.
 3. The proximity sensor of claim 1 wherein each of the lenses isdisposed between two of the cap feet.
 4. The proximity sensor of claim 1wherein one of the cap feet is disposed between the sensor area and thelight emitting device and is secured to the semiconductor die.
 5. Theproximity sensor of claim 1 wherein the second side of the encapsulatinglayer includes a plurality of apertures, each of the lenses beingdisposed below one of the apertures.